Compound metal spar



A. P. THURSTON ET AL COMPOUND METAL SPAR 2 sheets-sheet 2 Filed Dec. 10 191$ Patented May 8, 1923.

on-Iran PATIENT, YQPEFICIAE;

ALBERT P. THURSTON, or Lonnon-Ann HAMIn roN N.I'WYLIE, or BIRMINGHAM; "ENGLAND.

i COMPOUND METAL SPAR.

Application fiied necemb'erllfl, 1919. Seria1No. 343,890. f

To all whom it 'THURSTON, of the Royal Flying vCorps Club, Bruton Street, London, W., captainfin the Royal Air Force, a nd;.HAMrLT oN NEIL WYLIE, of 109 Colmore Row; Birmingham,

England, major in the Royal Air Force,

subjects of the King. of the United Kingdom of Great Britain and Ireland; have invented new and useful CompoundHMetal Spars, of which the following is a specification; This invention relates to compound metal spars and like structural members suitable for use as wing spars in aircraft and for other structural purposes.

.The invention relates. more particularly to sparsof 'irder formation which com prise oppositely disposed hollow booms or flanges connected by'webs, and adapted to resist longitudinal compression and, tension stresses. t V Q Stated, broadly this invention contemplates a compound metalfspar having a plurality of hollow booms orflanges symmetrically or otherwise disposed about a plurality of sheet metal webs. Stated another way this invention consists of ,a plurality of hollow, compression members and a plurality of hollowtension members connected by sheet metal webs to ,form a compound spar. a l y y This invention may bemore particularly stated to consist of a sheetmetalstructure comprising a plurality of web members connected together in the median plane of the structure and disposed in? splayed relationship and forming a'number of projecting arms in cross section, andtubular flange members located alongj'th'e outer edge of said projecting arms respectively, said tubular flange members "being constituted of loops having. outwardly curved extremities connected to the said respective projecting An important 'featureof this invention is the curving outwards of the free edges of the flange members and other parts of the structure inthe vicinity of joints."

Further features" of this invention will transpire in the'following description of the accompanying drawings, in which Figure lis afviewfin cross'seotion of one form of construction, t

Figure 2 is-a' view -in"cross jsection of another embodiment,

I r t Figure 3.18" a viewillustrating one v Be it knownv that we, ALB RT PETER OT IGIIIfO-I QBIIIGIIFTOI' the spar shewn in Figure 1,

Figure 4 ure '3 in elevation from the view-point indicated by marrow 1 a 1 Figure 5 is a view in cross section vof a furthermodification.

t Referring to Figure-1,,twohollow compressionmembers 1 and 2jare connected to two-J hollow tension, members 3, and- 4 by means of webs5 and 6 respectively, In the .form shewn the hollow members are formed rolling the edges of the: Web s. into t'ubular form and riveting; welding or otherwise securing the edges as at 7. The webs. 5 and 6 are similarly secured atjor nearthe centre line of the'spar as shewn at 8'. This construction. consists of osimilar sections one of whlch is reversed, and lends itself admirably to the employmentof standard sections of rolled sheet metalused in the manufacture of the rims.

The'reinforc'ement forsuch a spar is shewn 1n F1gure 3 andconsists of rigid frames or ribs 9 fitt ng snuglyand secured'by screws,

rivets orother means to the-webs 5 and 6.

These reinforcements f are disposed at: suitable intervals throughout the length of the spar. The frames or ribs 9 maybe solid or of ringer open form "and may'co-nsist of metal wood or any other suitable rigid material. The rivets 7' in certain forms of construction may be employed for securing'not only the rolled edge of the web but" also the frame orrib 9 as shewn in Figure 3.

" Further reinforcement, if"required, is obtained by fitting'a steel band 10 to embrace the sp-ar,"an d'-distance pieces 11 fitting the hollows in the webs andthen tightening up the band by means of a'bolt 12.: 'Tangs 13 m y 'be pressed out' of the steel band 10 or may be otherwise formed and secured there'- to as 'shewn inFigure 4; These'tangs serve in the case of w n spars ffor'aircraft for securing the wing ribs to the spar.

Referring'to F'ig'ure 2;the hollow compression members 1 and 2'are'connected by a web 14""and the members 3 and 4 are connected' by a web 15. Athird web 16 connects the transverse webs14and 15 together theseve'rahwebs being secured as shewn.

This construction is I suitable" for large aeroplane spars and the flattened hollow booms or flanges touch each 'otherat the top and is i'ai meaa dean O f Fig lent-way great.

bottom oi? ;the' spa-r; The major r axes 0f thesehollow members are symmetrica ll y inclined to the central vertical plane of the spar, and they are corrugated longitu'diw nally so that their cross sections have three" lobes.

The arrangement of Figure 5"shews :webs.

connecting the four hollow members. WVebs 17, 18, 19 and 20 have one edge "embraced by andsecured to the edges oi' each hollow 'ir'renibei respectively whilst web 21 is secured between adjacent edges of'the' above' men'- tioned webs. This arrangement facilitates manufacture and possesses the' advantage that owing to the spacing apartfofthe hollow members resistanceito' 'side bending 1s The construction shewn in Figures 21and 5fm'ayb reinforced in a manner similar to thatdescribed" with referen'ceto -Figure I 3.

1 In all cases 'the'hollow members and webs are suitably corrugated parallel to their ness of metal, We'cl'aim'.

length so that they may be made of sheet metal of small gauge yetsufiiciently strong to withstand shear and compression forces duef to lead on the spar;

'f To prevent'buckling Of t edges of the j ange' members," webs and "distance "pieces they are'fpreferably" curved outwards as 'shewn inthe drawings} 1 x g The holl memhersf are formed separately er integral with the webs according to circumstances and torsional rigidityis imparted m1 them by riveting or otherwise securing'their ed es.

' 'Wlfen three hollow members only" areemlo' ed in constructing thspar the number midi-ugly.

, disposition of the webs is inodified ac- Inall' cases the websmay consist oft'wo or more parts suitably connected together thefcompound 'web's'b'eing of 'a-single thicki p 1.1a sheet metal structu'recemprising a plurality "of web' members connected together the median plane ofthe structure and disposed in splayed relationship and forming a number of separate projecting arms in cross section, a' tubular member located along the outer edge of each of said projecting arms, and a plurality of reinforcing cross'frames disposedat'interva'ls be.-

tween said projecting arms. or v 2. A sheet metal structure comprising, a

plurality of longitudinally corrugated 'web ,members connected together rinjthe median plane of the structure and. disposed. in

splay'ed relationship and forming. a; number of separate projecting arms in cross section, atubular member located alongct'heiouter edge of each of said projecting arms and a plurality of reinforcing members disposed at intervals between said projecting arms.

3. A sheet metal structure comprising a plurality of web members eonnectedtogether the median plane (tithe-structure and disposed in splayed relationship and formin a: number, separate-projecting arm in across section, a tubular member located along the outer edge of each of said projecting arms, asp'lurality of reinforcing cross frames disposed at intervals between said projecting" arms; straps disposed at intervals embracing said web inembers,;,and means for tightening said straps.

" 1 4. A sheet metal ,structurecomprising .a

plurality of 3 longitudinally corrugated web members connected together. mum median plane of the structure and disposed-in splayed relationshipand forming a number 'ofiseparate projecting I arms in cross section, .a tubular membenloc'ate'd along the outer rality of reinforcing members disposedv at intervals between said "projecting 'arms, straps; disposed at, intervals embracing said Web member's, andmean's for tighteningsaid p i 1 l 5. A sheet metal structurecomprising a plurality of longitudinally corrugated web members: connected together in the fmedian .ed'ge' of each of said projecting arms, a plu- P o e. umatra ia d g l s'pqis fd n splayed relationship andfor'ming a number of projecting arms in cross section, a tubular member located along the outer edge of each of said projecting arms, and a plurality of reinforcing members disposed at intervals lbers' dis 'gosed in,sp ayed(relationship and forming, a number, of, projecting farms in cross section, one lohgitudinal tubularmember located along I the outer edge 7 of each of s' prql ctins a mband a p uy lity -r inforci'ng cross frames disposed at'intervals between said projecting, arms. r

. A sheet metalstlq ifltureIoiiiprising a plurality 0t longitudinally,corrugated cent1'ally,.connected Web v member i' disposed. ,in splayed relationship and ,forgmmg a number of separate v, pro ect ng; arms in cross section,

a longitudinal tubular member terminating .eacl1, ofsaidprojecting arms along the outer edge thereof, and a. plurality ofreinforcing members disposed atintervals between said projecting arms. v

9. A sheet metal structure comprising a plurality of centrally connected web members disposed in splayed relationship and forming a number of separate projecting arms in cross section, one longitudinal tubular member terminating each of said projecting arms along the outer edge thereof, a plurality of reinforcing cross frames disposed at intervals between said projecting arms, straps disposed at intervals embracing said web members, and means for tightening said straps.

10. A sheet metal structure comprising a plurality of longitudinally corrugated centrally connected web members disposed in splayed relationship and forming a number of separate projecting arms in cross section one tubular member terminating each of said projecting arms along the outer edge thereof, a plurality of reinforcing members disposed at intervals between said projecting arms, straps disposed at intervals embracing said web members, and means for tightening said straps.

11. A sheet metal structure comprising a plurality of. Web members disposed in eplayed relationship and forming a number of projecting arms in cross section, means for connecting said web members together along a central line, one tubular member along the outer edge of each of said projecting arms,

and a plurality of reinforcing members. disposed at intervals between saidprojecting arms.

12. A sheet metal structure comprising a plurality of web members disposed in splayed relationship and forming a number of projecting arms in cross section, means for connecting said web members together alonga central llne, one tubularmember along the outer edge of each of said project A. P. THUR-sToN.

H. N. WYLIE 

